1. Field of Disclosure
The present disclosure of invention relates to a display substrate, a method of manufacturing the display substrate and a display device having the display substrate. More particularly, example embodiments in accordance with the present disclosure relate to a display substrate having increased reliability, a method of manufacturing the display substrate and a display device having the display substrate.
2. Description of Related Technology
Generally, a liquid crystal display (LCD) device includes an LCD panel and a driving part for applying driving signals to the LCD panel. The LCD panel includes a display area and a peripheral area surrounding the display area. In the display area, a plurality of pixel parts are provided generally in the form of a matrix and are connected to gate wirings and data wirings and are configured to display images composed of corresponding pixels.
Conventionally, the gate wirings are driven by external gate driving integrated circuits. Recently however, in order to realize an LCD device having a small size, a light weight, a thin thickness, etc., it has been proposed that the gate driving circuitry which outputs the gate activation signals to the gate wirings should be monolithically integrated on the peripheral area of the LCD panel. The integrated gate driving circuitry generally includes a circuit part configured substantially for generating sequential gate activating signals and a plurality of wirings for delivering driving and control signals to the integrated gate driving circuitry. In one of the proposals, the integrated gate driving circuitry and associated wirings thereof are provided in an area that is covered by a liquid crystals material layer. (It is to be noted that this Description of Related Technology section may input disclosure that is not part of the prior art as publically known to those skilled in the relevant art.)
Given a relatively large LCD panel in which such an integrated gate driving circuit is directly formed at a peripheral area thereof and within an area covered by liquid crystals, where the large LCD panel is used for example as part of a relatively large-sized television set, the probability that defects such as open circuits or short circuits may be generated increases at crossing area of wirings of the LCD panel. The danger of such open circuits or short circuits is not typically of as much significance for LCD panels having a small size. However, among the many crossing wirings of a large-sized LCD panel, there is an increased chance that a fine crack or hole may develop in mechanically and/or chemically stressed areas where the developed crack extends through an insulation layer provided between wiring layers. The stress may develop due to differences of thermal expansion coefficients between one or more metal layers and corresponding protection/insulation layers provided in the crossing areas of wirings. The increased likelihood of shorting cracks or holes forming may be attributable to temperature increases associated with long use times, including long duration drivings of the integrated gate driving circuitry and due to temperature increases associated with use of high luminance backlight assemblies that are typically employed in large-sized TV sets meant for large audiences. One possible breakdown mechanism has, the overlapping liquid crystal molecules infiltrating through the thermally developed crack in such a way that an open circuit is generated due to chemical corrosion of exposed metal layers. Another possible breakdown mechanism has overlapping liquid crystal molecules infiltrating to an insulation layer between adjacent metals layers, for example by also infiltrating into a partially formed crack in a manner that weakens the voltage breakdown characteristics of the insulation and the latter leads to formation of further defects such as formation of open circuits and/or shorted together circuits or burnt out circuits. Consequently, formation of defects that can lead to formation of open circuits and/or shorted together circuits reduces the long term operational reliability of LCD panels including reducing the long term operational reliability of integrated gate driving circuits provided in large-sized LCD panels.